The present invention relates to an automatic document feeder for use in combination with an image processing apparatus such as copying apparatus, facsimile telegraph or the like. The apparatus has an original supporting station for supporting thereon an original and which is selectively operative in a first scanning mode for scanning one side of the original or in a second scanning mode for scanning opposite sides of the original.
Generally, a known automatic document feeder (ADF) used with, e.g., a copying apparatus comprises an original table for stacking thereon a plurality of originals to be copied. The originals, each having a front and back sides, are stacked on the original table in the state that each of the front sides of the originals faces upward.
In case of a plurality of single-sided image bearing originals having successive pages, the arrangement of the originals on the original table is such that the front side of the uppermost original has the first page, and the front side of the original adjacent to the uppermost original has the second page, while the front side of the lowermost original has the last page.
On the other hand, in case of a plurality of double-sided image bearing originals having successive pages, the arrangement of the originals oh the original table is such that the front side of the uppermost original has the first page, and the back side of the uppermost original has the second page, while the back side of the lowermost original has the last page.
The known ADF comprises an original receiving tray for receiving therein the original after the scanning of the original has been completed. The originals are fed one by one from the original table to the original supporting station of the apparatus in order from the lowermost original. At this stage, each of the originals is reversed upside down.
Accordingly, in case of the single-sided image bearing originals having successive pages the lowermost original having the last page arrives at the original supporting station in the state that the front side thereof, i.e., the last page, faces downward. On the other hand, in case of the double-sided image bearing originals having successive pages, the lowermost original having the last page arrives first at the original supporting station in the state that the front side thereof, i.e., the page before the last page, faces downward.
In case of the single-sided image bearing originals, the scanning of the under surface of the original having the last page is effected after the original has arrived at the original supporting station. Namely, the last page is copied at this stage. On the other hand, in case of the double-sided image bearing originals, the scanning of the under surface of the original having the last page is not effected at this stage.
In case of the single-sided image bearing originals, the original having the last page is then discharged from the original supporting station to the original receiving tray while being reversed upside down.
In this way, the single-sided image bearing originals are copied and then stacked on the original receiving tray in order from the last page.
On the other hand, in case of the double-sided image bearing originals, the original having the last page is removed from the original supporting station immediately after it has arrived at the original supporting station and then returned to the original supporting station through a reversing path while being reversed upside down. Accordingly, at this stage, the original on the original supporting station is in the state that the last page is oriented downward.
After the scanning of the under surface of the original having the last page has been completed, the original having the last page is removed again from the original supporting station and then returned again to the original supporting station through a reversing path while being reversed upside down. Accordingly, at this stage, the original on the original supporting station is in the state that the page before the last page is oriented downward.
After the scanning of the under surface of the original having the last page has been completed again, the original having the last page is discharged from the original supporting station to the original receiving tray while being reversed upside down. Accordingly, the original having the last page is stacked in the state that the last page is oriented downward.
In this way, the double-sided image bearing originals are copied and then stacked on the original receiving tray in order from the last page.
The above-mentioned known automatic document feeder has the following disadvantages.
It is often desired to affix successive page numbers to the transfer papers so as to correspond to those of originals having successive pages. For this purpose, the originals having successive pages have to be copied in order from the first page. However, in the known automatic document feeder, the originals are copied in order from the last page, as described above. In this case, it is necessary first to affix a last page number to the copied transfer paper. However, generally, it is impossible, in the known automatic document feeder or the copying apparatus, to determine a total number of the originals stacked on the original table. Therefore, it is impossible to affix successive page numbers to the respective transfer papers.
Further, when a paper jam of the original has occurred, it is necessary to reset the jammed original on the original table. In this case, in the known automatic document feeder, the remaining pages of the originals have to be removed from the original table, in order to place the jammed original below the remaining pages of the originals, resulting in a complicated resetting operation for the original.